An AH-64D Apache Longbow helicopter prepares for refueling operations during a training exercise at the Oberdachstetten Local Training Area, Ansbach, Germany, in 2013. (Georgios Moumoulidis/U.S. Army)

WASHINGTON — All Army National Guard helicopters have been grounded as units review safety policies and procedures following two crashes, the Guard announced Tuesday.

The stand-down, which took effect Monday, comes after two separate crashes of AH-64D Apache helicopters — one in Utah on Feb. 12 and another in Mississippi on Friday. Guard pilots Chief Warrant Officer 4 Bryan Andrew Zemek, 36, and Chief Warrant Officer 4 Derek Joshua Abbott, 42, died in the helicopter crash in Mississippi during a routine training flight.

“We are a combat force with helicopters training or on mission worldwide every day,” said Lt. Gen. Jon Jensen, director of the Army National Guard. “Safety is always at the top of our minds. We will stand down to ensure all our crews are prepared as well as possible for whatever they’re asked to do.”

Two pilots were hospitalized in Utah after their helicopter crashed during an exercise near the Army Aviation Support Facility at South Valley Regional Airport in West Jordan.

Both accidents are under investigation.

In 2023, following a collision of two Black Hawk helicopters in Kentucky that killed nine and a midair collision of two Apaches in Alaska, the Army ordered a safety stand-down, grounding all its helicopters.

Less than a month after the stand-down, two Apache pilots were injured in a crash during a training flight in Washington state.

The Army’s five-year safety review in 2020 found Apaches accounted for more than a quarter of its rotary-wing mishaps.

From 2016 to 2020, the combat helicopter was involved in 77 mishaps, resulting in $384.5 million in damage and 12 fatalities.

The report identified human error as the primary cause in 87% of class-A mishaps, which are those resulting in either destruction of the aircraft, a direct cost of at least $2 million or the death or permanent total disability of those on board.